Mixing particulate materials

Abstract

The invention relates to the mixing of particulate materials with a given mixing ratio and as part of a plant and process requiring the materials, comprising the steps of metering the materials separately in respective metering units running at least substantially continuously, permitting the materials to fall freely onto a horizontal conveyor belt with a planar surface with a distribution of the materials over the belt, and supplying the materials in a further free fall to a further processing zone as part of the process.

I claim: 
     
       1. A method of mixing particulate materials with a given mixing ratio, said method forming part of a process requiring said materials, comprising the steps of: providing particulate materials to at least two metering units,   metering said materials separately each in said respective metering unit, said metering unit operating at least substantially continuously,   crushing said particulate materials in said metering units,   distributing said materials by free fall onto a horizontal conveyor belt with a planar surface with a distribution of said materials over said belt,   matching the distribution rate of said materials with the speed of said conveyor belt such that said given desired mixing ratio is obtained, and   supplying said materials in a further free fall to a further processing zone as part of said process.   
     
     
       2. The method as claimed in claim 1 wherein said materials are distributed in superposed layers on said conveyor belt. 
     
     
       3. The method as claimed in claim 1 comprising the step of subjecting said materials on said belt to a magnetic field for the removal of pieces of metal therefrom. 
     
     
       4. An apparatus for mixing at least two particulate materials together with a given mixing ratio as part of a process plant requiring such materials in operation, said apparatus comprising a level, planar conveyor belt running to a processing zone within said plant, at least two metering units placed one after the other in succession in the direction of conveyance of said belt, each of said metering units including means defining a metering passage for flow of said particulate materials therethrough, said passage stretching from an inlet port to an outlet port, means for crushing said particulate materials positioned in said passage in each of said metering units, said units being adapted to meter said particulate materials at least substantially continuously, said outlets adapted to discharge said materials in a free fall onto said belt with a distribution onto substantially the full width of said belt, and means for adjusting the flow rate of said particulate material and the speed of said running conveyor belt such that said given mixing ratio of said particulate material is obtained. 
     
     
       5. The apparatus as claimed in claim 4 wherein said crushing means comprises a rotary ribbed roll placed in said metering passage for rotation about an axis running through said passage transversely thereof, said roll having ribs thereon bordering shallow trough-like depressions therebetween, said ribs being helical with respect to said axis and running from end to end of said roll. 
     
     
       6. The apparatus as claimed in claim 4 comprising one such ribbed roll located in each said passage, a stationary knife placed for cooperating with said ribs in defining a restricted gap as part of said passage, leading edges of said ribs being in the form of cutting edges for shearing said materials against said knife. 
     
     
       7. The apparatus as claimed in claim 6 comprising two such knives in said passage on two sides of the ribbed roll. 
     
     
       8. The apparatus as claimed in claim 6 wherein each unit comprises means defining an inlet duct for one of said particulate materials, a lining in said duct, said lining being parallel to said axis of said roll and being directed towards said gap and means for adjusting said lining in a direction that is radial in relation to a radial plane of the roll containing the gap. 
     
     
       9. The apparatus as claimed in claim 7 wherein said knives are detachably secured in place, at least one of said units having a shroud to take the place of one such knife and extending at least substantially concentrically about part of an outer face of the roll in said unit and past a lowest point of such outer face. 
     
     
       10. The apparatus as claimed in claim 9 comprising near a point of attachment of said shroud means supporting said shroud so that same may be rocked about a further axis parallel to said axis between an active position in which said shroud is parallel to said outer face and an inactive position and means for locking said shroud in both of said positions. 
     
     
       11. The apparatus as claimed in claim 5 wherein each metering unit comprises two such ribbed rolls in parallelism, means for driving said rolls in opposite directions at the same speed as each other with rib-to-rib rolling contact in the manner of meshing gears, and means for adjusting the distance between the axis of said rolls in each said unit and for turningly setting one roll in relation to the other. 
     
     
       12. The apparatus as claimed in claim 5 wherein said ribs on said rolls have such a helical angle about the axis of said roll that ends of each rib are spaced apart from each other in a circumferential direction by a distance equal to the circumferential pitch of the ribs. 
     
     
       13. The apparatus as claimed in claim 5 wherein said ribs have a rounded cross section. 
     
     
       14. An apparatus for mixing at least two particulate materials together with a given mixing ratio as part of a process plant requiring such materials in operation, said apparatus comprising: a level, planar conveyor belt running to a processing zone within said plant, at least two metering units placed one after the other in succession in the direction of conveyance of said belt, each metering unit has means defining a metering passage for flow of one of said particulate materials therethrough, said passage stretching from an inlet port to an outlet port, each said metering passage is vertical for supply of material to said roll and discharge of material therefrom, said passage having angular wall faces with respect to the vertical, a rotary ribbed roll placed in said metering passage for rotation about an axis running through said passage transversely thereof, said roll having ribs thereon bordering shallow trough-like depressions therebetween, said ribs being helical with respect to said axis and running from end to end of said roll, units being adapted to meter said particulate materials at least substantially continuously, and said metering units having outlets adapted to discharge said materials in a free fall onto said belt with a distribution onto substantially the full width of said belt. 
     
     
       15. The apparatus as claimed in claim 14 wherein said wall faces depart from the vertical from below. 
     
     
       16. The apparatus as claimed in claim 11 comprising means for changing the distance between the axes of the rolls, this said means being adapted to move one of said rolls together with a part of the means defining said passage tangent to said roll. 
     
     
       17. The apparatus as claimed in claim 5 wherein each unit comprises a housing defining a supply zone over its roll, said housing having a section able to be removed. 
     
     
       18. The apparatus as claimed in claim 5 wherein each unit comprises a housing defining a supply zone over its roll, said housing having a section able to be rocked out of place. 
     
     
       19. The apparatus as claimed in claim 5 wherein at least one of said rolls is hollow and is fitted with duct connection means for the supply and removal of heating fluid thereto and therefrom. 
     
     
       20. The apparatus as claimed in claim 4 wherein said conveyor belt has a discharge end that is adjustable in the direction of conveying of said belt. 
     
     
       21. The apparatus as claimed in claim 20 comprising a frame in which said conveyor belt is mounted, said frame being able to be adjusted in the direction of conveying. 
     
     
       22. The apparatus as claimed in claim 4 comprising a magnetic metal removing means placed between said units and a discharge end of said conveyor belt and running across said belt. 
     
     
       23. The apparatus as claimed in claim 4 wherein said conveyor belt is fitted with magnets and with a stripper means placed downstream from a discharge end of said belt.